How to save normal map texture from Blender?
Apparently what I was missing (Windows or Linux) is to check Save as Render box for PNG/OpenEXR. So the following worked for me to generate an external normal map texture:


Generate an image in Raw Color Space and with Float Buffer:




Note that Float Buffer is important, as 8bit dynamic range is not enough for a quality Normal Map. The Raw Color Space maps 8080FF as neutral color in Blender


Bake a normal map in Cycles or Blender Internal
Save resulting map as 16bit PNG with Save as Render checked.